In the first chapter of IT’S NOT HER, Mary Kubica describes in detail a violent double murder. Courtney Gray witnesses the brutal slaying of her sister-in-law, Emily, and Emily's husband, Courtney's brother, Nathan. Cleverly, while both narratives are in first person, Courtney narrates what is happening in the now, while her niece, Reese, explains the events of the preceding week.

Because Nathan married Courtney’s best friend, the families are close. Nathan and Emily have three children: rebellious 17-year-old Reese, moody 14-year-old Wyatt, and 10-year-old Mae. Courtney and her husband, Elliot, have a daughter, Cass, who is the same age as Mae. The girls are not only cousins but close friends. The two families have gone to a resort in northern Wisconsin for a week of togetherness, and while it is not as nice as they thought it would be, they are together.

"In addition to an intriguing plot and several people who might be guilty, Kubica creates the perfect amount of tension. The alternating narratives are extremely effective and add to the intensity of the story."

The only ones who really seem to be enjoying the togetherness are Cass and Mae. While they giggle, swim in the pool, and steal Elliot's iPad, tensions arise between Wyatt and Reese, and marital problems are exacerbated between Nathan and Emily. Reese meets and becomes infatuated with Daniel, the creepy guy who works at the resort cleaning the pool. While he's really repugnant to us, Reese is on the outs with her friends. Daniel is handsome and seems to like her, so she meets him at night for thrills. It assuages the loneliness she feels in her social life.

Courtney's account is about the events after the murder, what the police are doing to find the killer, and how the family is dealing with their new reality. Through her eyes, we see the strange actions of her husband and nephew. Both have exhibited some unsettling behaviors, and she wonders if either of them might be the culprit.

We learn about Daniel through Reese's account. In Kubica's capable hands, we are well aware of the angst of teenage years when girls feel every insecurity that social media has thrust upon them. Reese is grateful for the attention that Daniel is showing her, even as he keeps that attention hidden from the adults, insisting she meet him in the middle of the night. It's obvious that Kubica wants us to consider Daniel as a likely suspect in the double murder.

IT’S NOT HER is definitely a slow burn. At the start, Kubica sets up the atmosphere at the rustic, run-down resort. The endpapers in the book are striking, with a nighttime view that makes us envision the forest surrounding the cabins, even blocking most of the lake. It's also in the forest where Reese meets Daniel for midnight trysts. Kubica's descriptions are effectively detailed. We can almost smell the mildew and dust in the shabby cabins, along with the mold in the single bathroom they all share, and hear the creaking boards of the deck outside the cabin.

But as the two narratives continue, we are drawn into their lives. And as we understand all the foibles of the characters, the tensions between them, and the anger that some hide, we are truly invested in figuring out the killer's identity. Late last night, with 50 pages left to read, I lay awake going over all the characters to try to determine who it was. I was not successful.

In addition to an intriguing plot and several people who might be guilty, Kubica creates the perfect amount of tension. The alternating narratives are extremely effective and add to the intensity of the story. We realize that both narrators are slightly unreliable as they each have their own internal doubts and insecurities. Kubica also presents a twist after the shocking resolution that I am sure no one will guess.